bob bear, i'll bring you in, cnn contributor, former cia officer. welcome back. before we talk about the specifics of sarin, let me just throw this at you. is it possible at all that this man, this mad man, bashar al assad, is bluffing? >> oh, i don't think he's bluffing. we have to consider what he represents and that's a very small community, which feels under threat. it thinks it will be destroyed by sunni fundamentalists if it loses damascus or any other big cities. they have their backs to the wall. they say among themselves that when it comes to their lives or killing the rebels they will kill the rebels. in other words, yes, they will use the sarin, i've been dealing with the people for 30 years, they're almost a cult. what seems to us completely irrational decision, they're capable of. i don't know whether they have reached this point or not, but if things get bad enough in syria, i have no dowd they'll use it. >> on this sarin gas, i was reading about it, apparently there are two key components that make this gas and they're held separately, kept separat